FAP and colorectal carcinoma: Immunohistochemistry (IHC) of BCL9 and FAP (used as a C1-featured probe and marker of stromal cell infiltration)25 on a tissue microarray (TMA) of CRC samples (n = 89) revealed that stromal and ganglion cells have the highest level of BCL9 staining in normal colon mucosa (Supplementary Fig. 3a).